The older ABCD system of staging prostate tumors has largely been replaced by the TNM (Tumor, Nodes, Metastases) system, which gauges the severity of cancer on an escalating scale.
Tumor is microscopic and confined to prostate but is undetectable by a digital rectal exam (DRE) or by ultrasound. Usually discovered by PSA tests or biopsies.
Tumor is confined to prostate and can be detected by DRE or ultrasound.
In stage T3, the cancer has spread to tissue adjacent to the prostate or to the seminal vesicles. Stage T4 tumors have spread to organs near the prostate, such as the bladder.
Cancer has spread to pelvic lymph nodes (N+) or to lymph nodes, organs, or bones distant from the prostate (M+).
FDA Consumer magazine (September-October1998)